package com.toutiao.cut.util;


import java.io.Serializable;

import org.apache.log4j.Logger;

/** 
 * SparseArrays map integers to Objects.  Unlike a normal array of Objects, 
 * there can be gaps in the indices.  It is intended to be more efficient 
 * than using a HashMap to map Integers to Objects. 
 */  
public class SparseArray<E> implements Cloneable,Serializable {  
	
	private static final long serialVersionUID = 703486057005755064L;

	private static final Logger log = Logger.getLogger(SparseArray.class);
	
    private static final Object DELETED = new Object();  
    private boolean mGarbage = false;  
  
    private int[] mKeys;  
    private Object[] mValues;  
    private int mSize;  
    
    
    // 建个Index，这样比直接二分查找更快
    private int[] mIndex = null;
    private boolean isIndex = false;
    private int builkSize = 500;
    public void buildIndex() {
	   
	   gc();
	   
	   int size = mKeys[mSize-1];
	   size = size/builkSize+1;
	   
	   log.info("INDEX SIZE "+size);
	   
	   mIndex = new int [size];
	   
	   isIndex = true;
	   
	   for (int i = 0; i < size; ++i){
		   mIndex[i] = mSize+1;
	   }
	   
	   for (int i = 0; i < mSize; ++i){
		   int key = mKeys[i];
		   key = key/builkSize;
		   if (mIndex[key] > i){
			   mIndex[key] = i;
		   }
	   }
	   
	   isIndex = true;
	   
   }
    
    
    /** 
     * Creates a new SparseArray containing no mappings. 
     */  
    public SparseArray() {  
        this(10);  
    }  
  
    /** 
     * Creates a new SparseArray containing no mappings that will not 
     * require any additional memory allocation to store the specified 
     * number of mappings. 
     */  
    public SparseArray(int initialCapacity) {  
        //initialCapacity = ArrayUtils.idealIntArraySize(initialCapacity);  
  
        mKeys = new int[initialCapacity];  
        mValues = new Object[initialCapacity];  
        mSize = 0;  
        
        
    }  
  
    @Override  
    @SuppressWarnings("unchecked")  
    public SparseArray<E> clone() {  
        SparseArray<E> clone = null;  
        try {  
            clone = (SparseArray<E>) super.clone();  
            clone.mKeys = mKeys.clone();  
            clone.mValues = mValues.clone();  
        } catch (CloneNotSupportedException cnse) {  
            /* ignore */  
        }  
        return clone;  
    }  
  
    /** 
     * Gets the Object mapped from the specified key, or <code>null</code> 
     * if no such mapping has been made. 
     */  
    public E get(int key) {  
        return get(key, null);  
    }  
  
    /** 
     * Gets the Object mapped from the specified key, or the specified Object 
     * if no such mapping has been made. 
     */  
    @SuppressWarnings("unchecked")  
    public E get(int key, E valueIfKeyNotFound) {  
    	
    	int start = 0;
    	int len = mSize;
    	
    	if (isIndex){
    		int x = key/builkSize;
    		if (x < mIndex.length){
    			start = mIndex[x];
    			if (start == mSize+1)
    				return valueIfKeyNotFound;
    			if (x+1<mIndex.length)
    				len = mIndex[x+1]-mIndex[x];
    			else
    				len = mSize-start;
    		} else {
    			start = mIndex[mIndex.length-1];
    			len = mSize-start;
    		}
    	}
    	
        int i = binarySearch(mKeys, start, len, key);  
  
        if (i < 0 || mValues[i] == DELETED) {  
            return valueIfKeyNotFound;  
        } else {  
            return (E) mValues[i];  
        }  
    }  
  
    /** 
     * Removes the mapping from the specified key, if there was any. 
     */  
    public void delete(int key) {  
        int i = binarySearch(mKeys, 0, mSize, key);  
  
        if (i >= 0) {  
            if (mValues[i] != DELETED) {  
                mValues[i] = DELETED;  
                mGarbage = true;  
            }  
        }  
        
    }  
  
    /** 
     * Alias for {@link #delete(int)}. 
     */  
    public void remove(int key) {  
        delete(key);  
    }  
  
    /** 
     * Removes the mapping at the specified index. 
     */  
    public void removeAt(int index) {  
        if (mValues[index] != DELETED) {  
            mValues[index] = DELETED;  
            mGarbage = true;  
        }  
    }  
      
    private void gc() {  
        // Log.e("SparseArray", "gc start with " + mSize);  
    	log.info("SparseArray gc start with "+mSize);
  
        int n = mSize;  
        int o = 0;  
        int[] keys = mKeys;  
        Object[] values = mValues;  
  
        for (int i = 0; i < n; i++) {  
            Object val = values[i];  
  
            if (val != DELETED) {  
                if (i != o) {  
                    keys[o] = keys[i];  
                    values[o] = val;  
                    values[i] = null;  
                }  
  
                o++;  
            }  
        }  
  
        mGarbage = false;  
        mSize = o;  
  
        // Log.e("SparseArray", "gc end with " + mSize);  
        log.info("SparseArray gc end with "+mSize);
        
    }  
  
    /** 
     * Adds a mapping from the specified key to the specified value, 
     * replacing the previous mapping from the specified key if there 
     * was one. 
     */  
    public void put(int key, E value) {  
        int i = binarySearch(mKeys, 0, mSize, key);  
  
        if (i >= 0) {  
            mValues[i] = value;  
        } else {  
            i = ~i;  
  
            if (i < mSize && mValues[i] == DELETED) {  
                mKeys[i] = key;  
                mValues[i] = value;  
                return;  
            }  
  
            if (mGarbage && mSize >= mKeys.length) {  
                gc();  
  
                // Search again because indices may have changed.  
                i = ~binarySearch(mKeys, 0, mSize, key);  
            }  
  
            if (mSize >= mKeys.length) {  
                //int n = ArrayUtils.idealIntArraySize(mSize + 1);  
            	int n = mSize+1;
  
                int[] nkeys = new int[n];  
                Object[] nvalues = new Object[n];  
  
                // Log.e("SparseArray", "grow " + mKeys.length + " to " + n);  
                System.arraycopy(mKeys, 0, nkeys, 0, mKeys.length);  
                System.arraycopy(mValues, 0, nvalues, 0, mValues.length);  
  
                mKeys = nkeys;  
                mValues = nvalues;  
            }  
  
            if (mSize - i != 0) {  
                // Log.e("SparseArray", "move " + (mSize - i));  
                System.arraycopy(mKeys, i, mKeys, i + 1, mSize - i);  
                System.arraycopy(mValues, i, mValues, i + 1, mSize - i);  
            }  
  
            mKeys[i] = key;  
            mValues[i] = value;  
            mSize++;  
            
            isIndex = false;
        }  
    }  
  
    /** 
     * Returns the number of key-value mappings that this SparseArray 
     * currently stores. 
     */  
    public int size() {  
        if (mGarbage) {  
            gc();  
            isIndex = false;
        }  
  
        return mSize;  
    }  
  
    /** 
     * Given an index in the range <code>0...size()-1</code>, returns 
     * the key from the <code>index</code>th key-value mapping that this 
     * SparseArray stores.   
     */  
    public int keyAt(int index) {  
        if (mGarbage) {  
            gc();  
            isIndex = false;
        }  
  
        return mKeys[index];  
    }  
      
    /** 
     * Given an index in the range <code>0...size()-1</code>, returns 
     * the value from the <code>index</code>th key-value mapping that this 
     * SparseArray stores.   
     */  
    @SuppressWarnings("unchecked")  
    public E valueAt(int index) {  
        if (mGarbage) {  
            gc();  
            isIndex = false;
        }  
  
        return (E) mValues[index];  
    }  
  
    /** 
     * Given an index in the range <code>0...size()-1</code>, sets a new 
     * value for the <code>index</code>th key-value mapping that this 
     * SparseArray stores.   
     */  
    public void setValueAt(int index, E value) {  
        if (mGarbage) {  
            gc();  
            isIndex = false;
        }  
  
        mValues[index] = value;  
    }  
      
    /** 
     * Returns the index for which {@link #keyAt} would return the 
     * specified key, or a negative number if the specified 
     * key is not mapped. 
     */  
    public int indexOfKey(int key) {  
        if (mGarbage) {  
            gc();  
            isIndex = false;
        }  
  
        return binarySearch(mKeys, 0, mSize, key);  
    }  
  
    /** 
     * Returns an index for which {@link #valueAt} would return the 
     * specified key, or a negative number if no keys map to the 
     * specified value. 
     * Beware that this is a linear search, unlike lookups by key, 
     * and that multiple keys can map to the same value and this will 
     * find only one of them. 
     */  
    public int indexOfValue(E value) {  
        if (mGarbage) {  
            gc();  
            isIndex = false;
        }  
  
        for (int i = 0; i < mSize; i++)  
            if (mValues[i] == value)  
                return i;  
  
        return -1;  
    }  
  
    /** 
     * Removes all key-value mappings from this SparseArray. 
     */  
    public void clear() {  
        int n = mSize;  
        Object[] values = mValues;  
  
        for (int i = 0; i < n; i++) {  
            values[i] = null;  
        }  
  
        mSize = 0;  
        mGarbage = false;  
        
        isIndex = false;
    }  
  
    /** 
     * Puts a key/value pair into the array, optimizing for the case where 
     * the key is greater than all existing keys in the array. 
     */  
    public void append(int key, E value) {  
        if (mSize != 0 && key <= mKeys[mSize - 1]) {  
            put(key, value);  
            return;  
        }  
  
        if (mGarbage && mSize >= mKeys.length) {  
            gc();  
            isIndex = false;
        }  
  
        int pos = mSize;  
        if (pos >= mKeys.length) {  
            //int n = ArrayUtils.idealIntArraySize(pos + 1);  
        	int n = pos+1;
  
            int[] nkeys = new int[n];  
            Object[] nvalues = new Object[n];  
  
            // Log.e("SparseArray", "grow " + mKeys.length + " to " + n);  
            System.arraycopy(mKeys, 0, nkeys, 0, mKeys.length);  
            System.arraycopy(mValues, 0, nvalues, 0, mValues.length);  
  
            mKeys = nkeys;  
            mValues = nvalues;  
        }  
  
        mKeys[pos] = key;  
        mValues[pos] = value;  
        mSize = pos + 1;  
    }  
      
    private static int binarySearch(int[] a, int start, int len, int key) {  
        int high = start + len, low = start - 1, guess;  
  
        while (high - low > 1) {  
            guess = (high + low) / 2;  
  
            if (a[guess] < key)  
                low = guess;  
            else  
                high = guess;  
        }  
  
        if (high == start + len)  
            return ~(start + len);  
        else if (a[high] == key)  
            return high;  
        else  
            return ~high;  
    }  
}  